[MergeICmps][NFC] Add more assertions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324323 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/MergeICmps.cpp b/lib/Transforms/Scalar/MergeICmps.cpp
index 6856d58..f045b62 100644 (file)
--- a/lib/Transforms/Scalar/MergeICmps.cpp
+++ b/lib/Transforms/Scalar/MergeICmps.cpp
@@ -275,9 +275,11 @@ class BCECmpChain {
 
 BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi)
     : Phi_(Phi) {
+  assert(!Blocks.empty() && "a chain should have at least one block");
   // Now look inside blocks to check for BCE comparisons.
   std::vector<BCECmpBlock> Comparisons;
   for (BasicBlock *Block : Blocks) {
+    assert(Block && "invalid block");
     BCECmpBlock Comparison = visitCmpBlock(Phi.getIncomingValueForBlock(Block),
                                            Block, Phi.getParent());
     Comparison.BB = Block;
@@ -328,6 +330,7 @@ BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi)
     DEBUG(dbgs() << "\n");
     Comparisons.push_back(Comparison);
   }
+  assert(!Comparisons.empty() && "chain with a single complex basic block");
   EntryBlock_ = Comparisons[0].BB;
   Comparisons_ = std::move(Comparisons);
 #ifdef MERGEICMPS_DOT_ON
@@ -507,6 +510,7 @@ std::vector<BasicBlock *> getOrderedBlocks(PHINode &Phi,
                                            int NumBlocks) {
   // Walk up from the last block to find other blocks.
   std::vector<BasicBlock *> Blocks(NumBlocks);
+  assert(LastBlock && "invalid last block");
   BasicBlock *CurBlock = LastBlock;
   for (int BlockIndex = NumBlocks - 1; BlockIndex > 0; --BlockIndex) {
     if (CurBlock->hasAddressTaken()) {